Sensors comprising electrodes are used extensively in the assessment of clinical condition, for example in the monitoring of cardiac condition. The electrodes are placed in contact with the skin of the human body and the electrical physiological signals which result are examined.
Nevertheless, stability, noise and sensibility of the signals can be affected by different reasons; motion and long term acquisition of the signal are two of the most significant.
One of the physiological signals most affected by the different types of noise, as electrode contact noise or movement noise is the Electrocardiogram (ECG) signals. ECG is a long term analysis and to acquire a good signal it is crucial that the signal's parameters are stables.
As the ECG is a long term analysis, a garment that include an ECG sensor is essential to monitor this type of physiological signals in the daily live.
It is known in the state of the art, garments with sensors integrated in the textile. The sensor to be integrated in a garment must be a system minimal invasive, flexible, conformable to the human body including in movement, comfortable and resistant to repeated washing.
The current state of the art in textile sensors presents different drawbacks:    i) Low adhesion to skin. Each relative motion between skin and electrode causes alterations in the signal. This limitation is very significant in the context of use of electrodes during physical activity.    ii) Signal alterations. These are produced by the movement of the conductive fibers and the presence of wrinkles.    iii) Decrease of the signal quality with time. In some sensors to ensure the skin contact, liquids such as water or grease can be used between the contact layer and the skin. In dry environments it is not possible to remain the skin moisture level constant and the electric conductivity of the contact layer decreases.
The patent application EP1361819, which applicant was Polar Electro, OY., describes a sensor which comprises a contact layer including conductive fibers, and a moisture layer for retaining moisture on the top of the contact layer. The moisture layer retains secretory products from the skin, such as moisture and electrolytes. This enhances the contact between the skin and the contact layer and increases the electric conductivity of the contact layer, but the comfortable of the garment is minor as the humidity in the skin and inside the garment is increased.
The patent application EP2072009 describes a garment comprising at least one electrocardiogram sensor integrated into the garment comprising an electrode on the inside of the garment and arranged to contact a user's skin; and a resilient compressible filler provided between the garment and the electrode. The resilient compressible filler holds the electrode in place when the garment moves. The resilient compressible filler could be uncomfortable for the user.
The patent application US20100234715 describes a garment for measuring physiological signals. The garment including an electrode sensor coupled to an inner surface of a garment to make contact with the skin for detecting physiological signals; a signal connection line connected to the electrode sensor, a snap and a measurement unit. The electrode sensor unit is coupled to a desired portion of a garment using a coupling adhesive member which is may have opened frame shape for attaching edges of the electrode sensor to the garment. An anti slipping adhesive tape (member) may be formed along the border of the electrode sensor and the coupling adhesive member.
Thus, from what is known in the art, it is derived that the development of a sensor and a garment comprising the sensor which allow recording physiological signals, especially in movement, with improved adhesion properties but avoiding adhesive elements which produce skin irritations and with flexibility properties, is still of great interest.